Power transistors commonly employed in automotive and industrial electronics require a low on-state resistance (Ron), while securing a high voltage blocking capability. For example, a MOS (“metal oxide semiconductor”) power transistor should be capable, depending upon application requirements to block drain to source voltages Vds of some tens to some hundreds or thousands of volts. MOS power transistors typically conduct very large currents which may be up to some hundreds of Amperes at typical gate-source voltages of about 2 to 20 V.
Lateral power devices, in which current flow mainly takes place parallel to a first main surface of a semiconductor substrate, are useful for integrated circuits in which further components, such as switches, bridges and control circuits are integrated.
According to existing technologies, there are integration schemes which combine processes of manufacturing a vertical power device comprising a trench with further components such as logic circuits. Generally, a field plate is disposed in a lower portion of the trench, and a gate electrode is disposed in an upper portion of the trench. In such vertical power devices, a current flow mainly takes place perpendicularly with respect to the first main surface of the semiconductor substrate.
There is need of developing further lateral transistor concepts which may be manufactured utilizing known integration schemes.